Copolyesters of phthalic acids and hydantoins

Abstract

The disperse dyeability and moisture absorbency of a fiber and film forming poly(ethylene phthalate) ester is improved by including a hydantoin alcohol, hydantoin diacid, or a diester as a comonomer in the mixture of a phthalic acid or diester thereof and ethylene glycol to produce a random copolyester. The dyed fibers are useful for making various kinds of fabrics and articles made therefrom.

We claim: 
     
       1. A disperse dyeable, water-absorbent polyethylene phthalate copolyester comprising units randomly spaced in its chain obtained by esterification of a phthalic acid or diester thereof and ethylene glycol with a hydantoin of the formula ##STR5## wherein R is hydrogen, lower alkyl, aryl, aralkyl, alkaryl or heterocyclic group which may be the same or different, X is --OH, --COOH or --COOR, R 1  is lower alkyl, n is an interger of 1 to 6 when X is --COOH or --COOR 1  and n is an integer of 2 to 6 when X is --OH. 
     
     
       2. The copolyester of claim 1 containing from about 2 to about 15 mol % of the hydantoin units based on the mols of the phthalic acid or diester. 
     
     
       3. The copolyester of claim 1 wherein the phthalic acid is terephthalic acid. 
     
     
       4. A fiber comprising the copolyester of claim 1 wherein the units in the chain are derived from dimethyl terephthalate, ethylene glycol and a hydantoin of the formula ##STR6## wherein R is hydrogen lower alkyl, aryl, aralkyl, alkaryl or heterocyclic group which may be the same or different, X is --OH, --COOH or --COOR 1 , R 1  is lower alkyl, n is an integer of 1 to 6 when X is --COOH or --COOR 1  and n is a integer of 2 to 6 when X is --OH. 
     
     
       5. The fiber of claim 4 wherein the units of the chain are derived by esterification of dimethyl terephthalate, ethylene glycol and 1,3-bis(methyl n-propionate)-5,5-dimethylhydantoin or 1,3-bis(2-hydroxyethyl)-5,5-dimethyl hydantoin. 
     
     
       6. A method for improving the disperse dyeability of a polyethylene phthalate based polyester which comprises simultaneously esterifying a phthalic acid monomer or diester thereof, ethylene glycol and a monomeric hydantoin diacid, hydantoin diester of hydantion diol to form a copolyester containing in its chain randomly spaced units derived from the hydantoin. 
     
     
       7. The method of claim 6 wherein dimethyl terephthalate, ethylene glycol and 1,3-bis(methyl n-propionate)-5,5-dimethylhydantion or 1,3-bis(2-hydroxyethyl)-5,5-dimethyl hydantoin are esterified. 
     
     
       8. The method of claim 6 wherein from about 2 to about 15 mol % of the hydantoin units based on the mols of phthalic acid or diester are esterified with the other components. 
     
     
       9. The method of claim 6 wherein dimethyl terephthalate and ethylene glycol are esterified with a hydantoin of the formula ##STR7## wherein R is a lower alkyl, aryl, aralkyl, alkaryl or heterocyclic group which may be the same or different, X is --OH, --COOH or --COOR 1 , R 1  is lower alkyl, n is an integer of from 1 to 6 when X is --COOH or --COOR 1  and n is an integer of from 2 to 6 when X is --OH. 
     
     
       10. A one-step method for making a polyethylene phthalate copolyester having improved disperse dyeability over a homopolyester which comprises simultaneously esterifying a phthalic acid or diester thereof, ethylene glycol and a hydantoin diacid, hydantoin diester or hydantoin diol. 
     
     
       11. The method of claim 10 wherein dimethyl terephthalate and ethylene glycol are esterified with a hydantoin of the formula ##STR8## wherein R is a lower alkyl, aryl, aralkyl, alkaryl or heterocyclic group which may be the same or different, X is --OH, --COOH or --COOR 1 , R 1  is lower alkyl and n is an integer of from 1 to 6 when X is --COOH or --COOR 1  and n is 2 to 6 when X is --OH. 
     
     
       12. The method of claim 10 wherein from about 2 to about 15 mol percent of the hydantoin based on the mols of phthalic acid or diester is esterified with the other components. 
     
     
       13. A spinnable copolyester having improved disperse dyeability and improved moisture retention comprising units obtained by removing the hydrogen atoms from the hydroxyl groups of a phthalic acid, units obtained by removing the hydrogen atoms from azelaic acid, units obtained by removing the hydroxyl group of a hydantoin alcohol or hydrogen atoms from a hydantoin diacid and units obtained by removing the hydroxyl groups from a glycol randomly joined together.